Lyophilized pegylated murine IL22 although stable at room temperature for several days, should be stored desiccated below -20C. Upon reconstitution at 0.1mg/ml pegylated mouse IL22 and up to 2mg/ml, filter and sterilized, the protein can be stored at 4 degrees Celsius for several weeks making it suitable for long term infusion studies using osmotic pumps. At lower concentration addition of a carrier protein (0.1% HSA or BSA) is suggested. Please prevent freeze-thaw cycles.